The applied anatomical study for transethmoidal-sphenoid optic nerve decompression under endoscopy / 中华显微外科杂志

ABSTRACT

Objective To explore the anatomy for transethmoidal-sphenoid optic nerve decompression under endoscopy and its significance in operation. Methods Fifteen cases (30 sides) of formalin-fixed adult optic canal specimens were dissected under the microscope. The anatomic characteristics of the optic canal and its adjacent were observed, and the relative parameters were evaluated according to nasal endoscopic approach. Results ①The relationship between the optic carotid triangle(OCT)with the optic canal, the ophthalmic artery, the cavernous sinus and the internal carotid artery were invariable, its present ratio were in 66.7%. ②The mean distance from the front margin of nasal columella floor to medial wall of the orbital opening, middle portion and the cranial opening in the optic canal were (72.79 ± 5.40)mm, (75.85 ± 5.10)mm and (79.34 ± 4.95)mm, respectively, and the elevation angles were (39.45 ± 3.68)°, (37.30±4.24)°and (35.45 ± 4.16)°, respectively. ③The mean thickness of sheath in the medial wall of the orbital opening,middle portion and the cranial opening were (0.70 ± 0. 18)mm, (0.51 ± 0.15)mm and (0.49-0.22)mm,respectively. The difference in thickness between the orbital opening and middle portion, the cranial opening were very remarkable(P ＜ 0.01 ). ④The lateral deviate distance from medial wall of the orbital opening, middle portion and cranial opening to sagittal median plane of cadaveric were 1/2 (12.69 ± 2.73)mm、1/2( 19.61± 3.47)mm and 1/2 (25.79 ± 3.23)mm, respectively. Conclusion OCT is the most reliable anatomic landmark to locate the optic canal, and the key point is at the orbital opening of the optic nerve in the optic nerve decompression. It is secure and feasible to cut the sheath from the place where the medial wall crosses the superior wall of the optic nerve.